English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

A 25 $\rm deg^2$ region, including the M81 complex (M81, M82, NGC 3077), NGC2976 and IC2574, was mapped during ~3000 hours with the DRAO synthesistelescope. With a physical resolution of ~1 kpc, these observations allow us toprobe a large region down to column density levels of ~$\rm 1\times10^{18}\,cm^{-2}$ over 16 $\rm km\, s^{-1}$, mapping the extent of the HI arm connectingthe system and NGC 2976, and resolving the HI clouds adjacent to the arm. Theobservations also reveal a few clouds located between the system and IC 2574,probably tidally stripped from a past interaction between the two systems.Given the regular velocity distribution in the HI envelope of the system, weattempt and derive an idealised large-scale rotation curve of the system. Weobserve a flat trend for the rotation velocity of the overall system from 20kpc out to 80 kpc, well beyond the outskirts of the M81 disk, although withasymmetries like a wiggle at the vicinity of M82. This supports the assumptionthat intergalactic gas and galaxies in the system participate to a large-scaleordered rotation motion which is dominated by M81. Also, our HI analysis of thegroup further supports the hypothesis that the galaxies forming the systemmoved closer from afar, in agreement with numerical simulations.

A 5deg x 5deg deep HI survey of the M81 group